PTK2 and gastrointestinal stromal tumor: A series of studies based on the microarray and qRT-PCR analysis identified the differential expression levels of miRNAs between imatinib treated GIST patients with and without secondary resistance and highlighted the functional role of miRNA-125a-5p on secondary imatinib resistance by regulating PTPN18 to affect the phosphorylation of FAK (Akcakaya et al., 2014; Huang et al., 2018).